Updated December 7, 2021:
This project will significantly increase the genetic diversity in US soybean germplasm in both the public and private sectors, expanding the genetic potential for improved seed composition, productivity in diverse and changing environments, and profitability for US soybean farmers. The ultimate goal is to have at least one commercial seed company commercialize a new soybean variety that is derived from lines and information from this project in the next 5-10 years. The lasting impact of this project will be the transformation of the US commercial soybean germplasm pool to include 3x or more of the PI accessions than in the current gene pool, setting the stage for continued, long-term success for US soybean farmers.

Annual reports summarizing the multi-environment, multi-year tests that include yield and other important agronomic traits, seed protein and oil concentration, calculation of seed oil yield (lb/bu), meal protein percentage, meal protein yield (lb/bu), amino acid composition, composition for major soluble carbohydrates (sucrose, raffinose, stachyose), seed weight, and other information were developed each year. These Diversity Cooperative Tests involved 11 or more university, USDA and industry partners each year with 18 or more locations evaluating 220+ diverse, high-yielding soybean lines each year in Maturity Groups I, II, III and IV. Copies of the annual reports were shared each February with the USB/Smith Bucklin representatives working with this project and should be on file and available to USB members who want to review them. All cooperators received the annual report for their use in decision making for line advancements, crossing, and other research.

This was an interdisciplinary project that involved breeding, genetics, genomics, and biotechnology, working on different aspects of soybean genetic diversity to improve soybean yield, meal protein, and profitability for US soybean farmers. The diverse lines developed and tested in this program have 3x to 4x the contributions from genetically diverse soybean accessions compared to the foundation of the current US commercial germplasm pool.

All 400+ genetically diverse experimental lines were evaluated by our industry partners as well. Several lines were transferred to industry breeding programs through MTAs and/or license agreements for use in their development of commercial cultivars.

Results from our analysis of amino acid composition in the elite, high-yielding lines in the Diversity Cooperative Tests across the north central USA in Maturity Groups I, II, III and IV, indicate that there is no difference in amino acid composition in the high-yield lines with increased seed protein concentration or better oil/protein balance. Similar results were seen from our evaluation of amino acid composition of the ultra-high protein lines from long-term selection in either exotic or elite genetic backgrounds. Seed protein concentrations exceeded 55% on a dry matter basis, with no decline in protein quality as protein concentration increased. In fact, in some lines, we actually saw an increase in the percentage of sulfur-containing amino acids in the higher-protein lines. The observation that there are no negative relationships between sulfur containing amino acids and yield is good news for soybean farmers and for breeding. We can develop and high-yielding lines that have high-quality amino acid composition in the high-protein meal.
Fine mapping of the QTL regions on Chromosomes 15 and 20 led to identification of candidate genes in each of those regions. Modulation of gene expression through transformation, and evaluation of the transformed progenies in greenhouse and field environments showed slight increase in seed protein concentration in some transgenic lines, potentially confirming the targeted candidate gene as the causal gene for the high-protein phenotype.
Significant progress was made with development of lines with improved seed quality for use in the early soybean production system in the southern US. In addition to improved resistance to heat and fungal damage, improved seed protein concentration also was achieved.

Our DNA sequencing of all of the entries in the Diversity Cooperative Tests allowed prediction of cross performance and more informed selection of parents for population development. We also are developing tools for better visualization of genetically diverse regions on each chromosome for every line, so specific regions may be targeted for enhancing favorable genetic diversity in commercial germplasm.

These accomplishments lay the foundation for sustained and enhanced growth in productivity, quality, and profitability for soybean farmers.